The Effect of Desaturation on the Static and Cyclic Mechanical Response of Dense Sand

Small amounts of soil desaturation can substantially impact the undrained static and cyclic response of sand when compared to the fully saturated case. Due to its impact on undrained behavior, desaturation can increase the strain hardening behavior of loose sand subject to a monotonic static load and is an emerging technique for mitigation of the liquefaction potential of sands. Several investigators have demonstrated the increase in the cyclic strength, decrease in pore pressure generation, and reduction in seismic settlement that accompanies small amounts of desaturation in a loose sand. However, the potential impacts of desaturation on the undrained static response of dense soils is less well studied. In this work, results from the cyclic and static undrained testing of a natural beach sand and Ottawa 20-30 silica sand show that, while desaturation does significantly improve the cyclic response of dense sand, desaturation may also lead to a decrease in the monotonic compressive strength of sand initially dense of critical state. The impact of this result on the implementation of liquefaction mitigation via desaturation is discussed.